2019-01-14 General Committee Agenda - Attachment 3 to Item 2 - Monitoring of Noosa River Oyster Reefs Nov 2018

Oyster reef unit installations
The installation of oyster reef units to the Noosa River was done during a period of three
days, from 20 to 22 November 2017 (Figure 4). All works and surveys were conducted by a
team comprising professionals of Noosa Jetty Builders, and marine scientists from the
University of the Sunshine Coast. All oyster reef units and signs were installed exactly
according to specifications set out in the permit conditions and any instructions provided
regarding procedures (Table 1). All reef units are located to avoid any damage to marine
plants or surrounding ecosystem (Table 1, Figure 4). Key observations during the placement
of the reef units and associated signage include the following:
    • No marine plants were disturbed during the installation of the reef units or signs.
        Before each reef unit was placed on the seafloor, we carefully examined the site to
        ascertain that no seagrass, mangrove aerial roots, or any other marine vegetation
        was present. This ensured that no direct placement impacts occurred at any of the
        sites (Table 1).
    • All operations were localised to the immediate site where reef units were sunk onto
        the seabed. Thus, no habitat outside the RAA area was impacted in any form by the
        reef units or the signage.
    • Poles holding the signs were installed using a narrow water jet ‘spear’. Use of this
        gear ensured that only a very narrow (< 20 cm diameter in all cases) area of the
        seabed was disturbed (Figure 4). Sign posts were then driven further into the
        substrate, to a mean depth of 2.7 m (min 1.8 m, max 3.5 m; Table 1), using a post
        driver (Figure 4).
    • According to engineering specifications, we used marine grade hardwood stakes
        (sourced from the Australian Hardwood Stake Company) to secure the reef units on
        the seafloor. The stakes were hammered into the seabed to a mean depth of 0.9 m
        (min 0.5 m, max 1.2 m) - depending on hardness of the seabed (Table 1), at a mean
        angle of 82.4º (min 75 º, max 90 º).
    • Pre- and post-installation photographs and videos of all sites are available
        electronically (OneDrive folder). Full access to the all electronically stored imagery
        has been provided to Noosa Council. In addition, we are happy to grant access to
        whoever may require it (please email: [email protected]).




Figure 4 The resulting very small footprint of sign posts following installation by the water jet
(left) and a completed oyster reef in Weyba Creek (right).




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